Abstract
An efficient method for the synthesis of N2-modified guanosine nucleotides such as N2-[benzyl-N-(propyl)carbamate]-guanosine-5′-O-monophosphate, N2-[benzyl-N-(propyl)carbamate]-guanosine-5′-O-diphosphate, N2-[benzyl-N-(propyl)carbamate]-guanosine-5′-O-triphosphate, and N2-[benzyl-N-(propyl)carbamate]-N7-methyl-guanosine-5′-O-diphosphate, starting from the corresponding nucleotide is described. The overall reaction involves the condensation between the exocyclic amine of guanosine nucleotide with 3-[(benzyloxycarbonyl)amino]propionaldehyde in aqueous methanol, followed by reduction using sodium cyanoborohydride to furnish the corresponding N2-modified guanosine nucleotide in moderate yield with high purity (>99.5%).